Stories
Slash Boxes
Comments

SoylentNews is people

posted by janrinok on Friday January 26 2018, @02:41AM   Printer-friendly
from the sounds-simple dept.

A new study suggests a biosignature that the James Webb Space Telescope could search for:

The new study looks at the history of life on Earth, the one inhabited planet we know, to find times where the planet's atmosphere contained a mixture of gases that are out of equilibrium and could exist only in the presence of living organisms — anything from pond scum to giant redwoods. In fact, life's ability to make large amounts of oxygen has only occurred in the past one-eighth of Earth's history.

By taking a longer view, the researchers identified a new combination of gases that would provide evidence of life: methane plus carbon dioxide, minus carbon monoxide.

"We need to look for fairly abundant methane and carbon dioxide on a world that has liquid water at its surface, and find an absence of carbon monoxide," said co-author David Catling, a UW professor of Earth and space sciences. "Our study shows that this combination would be a compelling sign of life. What's exciting is that our suggestion is doable, and may lead to the historic discovery of an extraterrestrial biosphere in the not-too-distant future."

Also at Popular Mechanics.

Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life (open, DOI: 10.1126/sciadv.aao5747) (DX)


Original Submission

Related Stories

Oxygen Ions Could Act as a Biomarker for Finding Life on Exoplanets 12 comments

The presence of large quantities of oxygen ions may be able to distinguish habitable exoplanets with life from barren exoplanets in the habitable zone (resembling Venus or Mars):

Like Earth, Venus and Mars are small rocky planets; they have permanent atmospheres like Earth, and their atmospheres are exposed to the same solar radiation as Earth's. Data from the Pioneer Venus Orbiter and the Viking descent probe on Mars show that they have very similar ionospheres to each other—which don't contain a lot of atomic O+ ions. Know what else Venus and Mars are missing? Photosynthesis.

[Astronomy PhD candidate Paul] Dalba's contention is that photosynthesis on a planet's surface, which generates a surfeit of molecular oxygen, is the only thing that can account for these atomic O+ ions in a planet's ionosphere. The mere existence of life throws a planet's atmosphere out of chemical balance. O+ would be a neat biomarker because there isn't a numerical cutoff required—just the dominance of O+ among the ionic species in the upper atmosphere would indicate "thriving global biological activity" on the planet below.

Dalba claims that Venus and Mars act as negative controls, demonstrating that planets like Earth but lacking life don't have this O+ layer. Some may think that continuous volcanic activity on the surface could also generate enough oxygen, but Dalba doesn't. Chemistry involving water and UV light [open, DOI: 10.1038/srep13977] [DX] can also release oxygen. But the amount of water on Earth is insufficient to account for the requisite oxygen content, so he thinks that the presence of water on other planets wouldn't make enough oxygen there either.

Atomic oxygen ions as ionospheric biomarkers on exoplanets (DOI: 10.1038/s41550-017-0375-y) (DX)

Related: Nitrogen in Ancient Rocks a Sign of Early Life
Oxygen Ions From Earth Escape to the Moon
Researchers Suffocate Hopes of Life Support in Red Dwarf "Habitable Zones"
Seven Earth-Sized Exoplanets, Including Three Potentially Habitable, Identified Around TRAPPIST-1
Cosmic Methyl Chloride Detection Complicates the Search for Life on Exoplanets
Mars Colonists Could Produce Oxygen by Making a Plasma Out of Atmospheric Carbon Dioxide
Analysis of Microfossils Finds that Microbial Life Existed at Least 3.5 Billion Years Ago
To Detect Life on Other Planets, Look for Methane, Carbon Dioxide, and an Absence of Carbon Monoxide


Original Submission

This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
(1)
  • (Score: 1) by tftp on Friday January 26 2018, @04:53AM (4 children)

    by tftp (806) on Friday January 26 2018, @04:53AM (#628100) Homepage
    Like generals, who are always preparing for the last war, the scientists look for signs of a civilization that is exactly like their own. This is, perhaps, useful if they intend to colonize that planet. But if they have a far simpler task of detecting life... probably it's futile. We still don't know whether there is life on Mars. We simply don't know all signatures of life, and we cannot detect them over such a distance. It might be hard to recognize them even from orbit of that planet - say, it's 100% ocean. Sorry for pessimism.
    • (Score: 4, Insightful) by bzipitidoo on Friday January 26 2018, @06:21AM (2 children)

      by bzipitidoo (4388) on Friday January 26 2018, @06:21AM (#628122) Journal

      This isn't looking for civilization, it's looking for life. On Earth, civilization has existed for 0.000005 billion years, while life had been around for 4 billion years. We're far more likely to find a world full of alien microscopic life than an alien civilization.

      Futile? Not at all. Just because we have not detected any life anywhere else in our solar system is no reason to despair of ever finding any. We've hardly had a chance to look yet, and the sample size in our own solar system is very, very small. It's been only 25 years that we've known for sure that there are even exoplanets! Before the discovery of 51 Pegasi b, some wondered if having planets in orbit was very rare or even unique. We'll be taking a closer look, be sure of that. And what we may find is that life is everywhere. I would not be the least surprised if 1 in 10 stars or more is host to a planet with alien bacterial life. I suspect we underestimate (underguestimate?) because we are prejudiced and like to think we and our planet are so special.

      • (Score: 1, Informative) by Anonymous Coward on Friday January 26 2018, @08:36AM (1 child)

        by Anonymous Coward on Friday January 26 2018, @08:36AM (#628151)

        You completely missed his point. It's not about civilizations or the probability of finding life, it's about that the life we are looking for is earth-based life.

        For example, looking for the lack of carbon monoxide. Carbon monoxide is poisonous to earth-based life, at least oxygen-breathing earth-based life. It won't be poisonous to a carbon monoxide breathing alien life form, or one that doesn't breathe in the first place.

        And that's just carbon-based life. Who knows what silicon-based life looks like.

    • (Score: 2, Interesting) by khallow on Friday January 26 2018, @07:35PM

      by khallow (3766) Subscriber Badge on Friday January 26 2018, @07:35PM (#628447) Journal
      The actual prescription is to look for planetary surfaces that are not in chemical equilibrium. They're saying that for Earth, this potential signature of life would have been present for several billion years, well before the creation of an oxygen-rich atmosphere.
  • (Score: 3, Interesting) by Freeman on Friday January 26 2018, @04:32PM (6 children)

    by Freeman (732) on Friday January 26 2018, @04:32PM (#628314) Journal

    I find it interesting that we haven't detected any life outside of our Planet. The Universe is mind-bogglingly huge though, so I guess it's not terribly surprising.

    As a Christian I believe in extraterrestrial life, just not in the same way an Atheist would believe in it. It would be some kind of hubris to think that God only made the Angels and Humans. When we also believe he created the entire Universe. We are special, because He made us in His own image. In the same way that the birds were made after their kind. We were made in the image of God, but unlike the animals He shaped Adam with His own hands and breathed into him the breath of life. We were also given the freedom of choice. We know that at least the Angels were given the freedom of choice as well, since Satan rebelled against God and a fifth of the Angels went with him.

    Anyway, my point is God, has likely created many forms of life and they each have their own place in the Universe. The awesome thing, is we will eventually get to visit them as we will be remade to be the perfect beings we were meant to be and will be able to travel to see them. Whether it's flying in a similar manner to the Angels or perhaps via the Spirit of God in a manner we might call Teleportation. God can seemingly appear at one place and then instantly appear in another location, so far away that we could only call it Teleportation. Since, we will be made to be perfect in His likeness at the resurrection, we will be able to travel to these amazing places He has created.

    You can call me crazy, but I have faith that He will keep His promises.

    So, yeah, I believe there is all manner of Life out there in the Universe and that it's awesome. It's part of the reason why I love Astronomy, because we can see a glimpse of the Awesome things there are out there. We generally think in terms of Life as being tied to Carbon life forms. But, if life is in the Spirit, why can't some of those beautiful stars you see out there, not be sentient? Perhaps that is Crazy, but we don't know right now. We will know when Christ returns to bring us to heaven and to re-create the luscious garden that the Earth was supposed to be.

    --
    Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
    • (Score: 2) by bzipitidoo on Friday January 26 2018, @05:22PM (5 children)

      by bzipitidoo (4388) on Friday January 26 2018, @05:22PM (#628345) Journal

      Christianity has a lot more challenges ahead. Historically, the church hasn't handled it too well. 400 years ago, the fact that the Earth may not be the Center of the Universe after all didn't go down well with a lot of Christians. In the Middle Ages, the church backed a lot of astronomy. It's like they felt they had to, to maintain and enhance credibility with the masses by having superior knowledge of the heavens and celestial events, and not because they were genuinely curious. Within that context, their attitude towards Galileo is more comprehensible. Some priests must have felt he was a traitor for contradicting their astronomical dogma.

      Today, many so called Christians are still fighting to deny evolution. It's so damaging to the religion. Makes Christians and Christianity look stupid. Painted themselves into a logical corner again, and now they're trying to rip up the canvas to get out. Why can't we be closely related to monkeys, and still be "created in the image of God"? And then, some adopt denial of Global Warming and idiotically and with barely any justification, treat that position like it's a pillar of the faith that if proven wrong, will bring all Christianity down with it!

      The core of Christianity is the morals that Jesus preached. The miracles are merely a sideshow, very likely hugely exaggerated or entirely invented events hoked up to wow the credulous. They're not that important, and if Christians had more sense, they'd quit clinging to them as "proof" of the divine provenance of the Bible and Jesus.

      Those of weak faith, who lean on the miraculous, who are shaken to the core every time a book and movie like The Da Vinci Code comes out, could really use some help understanding faith and science. If only they'd listen, which, sadly, most won't.

      • (Score: 2) by Freeman on Friday January 26 2018, @06:22PM (4 children)

        by Freeman (732) on Friday January 26 2018, @06:22PM (#628384) Journal

        Believe it or not, there's a lot of Protestant descendant Christians who also think the Catholic Church was and / or is corrupt and that the Catholic Church doesn't follow the core teachings of Jesus. The core teachings of Jesus are embodied in the Ten Commandments with Jesus himself having given a summation of the "Laws of the Prophets". "37Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. 38This is the first and great commandment. 39And the second is like unto it, Thou shalt love thy neighbour as thyself. 40On these two commandments hang all the law and the prophets." --Matthew 22:37-40 A Christian who doesn't follow the Ten Commandments, is living in ignorance.

        Christians deny evolution as the "Science" of evolution takes giant leaps of faith that their wacko scheme of billions of years ago we started as a big bang or whatever happens to be popular to describe the evolution of life, nonsense. I have a greater likelihood of growing a leg out of ear than some of the the pseudo scientific evolution teachings. Evolution is built on the faith that we came from something, so why not monkeys. I know that the evolution of the species is likely true in that some species of birds and / or frogs, etc. may adapt to their environment in such a way that they evolve. Just stop trying to feed me the billions of years life creation story or the millions of years dinosaur theories. How likely is it that we're coming across Huge deposits of dinosaur remains that are recognizable as such after millions of years of them being buried? Why would there be evidence of anything after that length of time? Or even more crazy is finding Fully Frozen Woolly Mammoth carcasses. 40,000 years in frozen ice and it isn't some sort of unidentifiable yuck? Sure, ice, it keeps things frozen / preserved better. But, for 40k years, you've got to be kidding me.

        Global Warming has nothing to do with the "Evolution debate". I could have a relatively sane conversation about Global Warming, if it wasn't punctuated with Crazy talk. Yes, I don't want the world to become some kind of desert. No, I don't think we're going to have that issue in the next 100 years. No, I don't think the polar ice caps are going to melt in that time, either. That Doesn't make me a Global Warming / Climate Science Denier. That makes me a fairly reasonable human being. Yes, I don't like bunches of smog in the air and Coal Stacks pouring pollutants in the air. Guess what, I like breathing, that seems to be a novel concept to some people. I really do like the idea of Solar Power, but it's not as proven of a source as Coal / Oil. Sure, it may be the golden rainbow we need, but that knowledge will hopefully come in the future. Yes, greedy people/corporations will be greedy and not care one bit about the environment or anyone else. There's a huge uphill battle for anything that encroaches on well entrenched industries. That doesn't mean we'll stick with the horse and buggy, though. Change doesn't usually happen overnight, unless it's violent and / or forced in some way. Whether through rule of law, violent enforcement, or due to sheer survival. We're surviving just fine at the moment, government and certain corporations don't have much incentive to push it, and there are no rebellions happening because of Global Warming. While the USA is huge, and we can do better, we aren't "The Problem" when it comes to pumping vast amounts of pollutants into the air. Developing countries are much more of a problem in comparison. Especially large economies and industries in India and China. http://www.news.com.au/travel/world-travel/countries-with-the-worst-air-pollution-ranked-by-world-health-organisation/news-story/524a5b1df6311d122892c0b7de940934 [news.com.au] Though, according to the WHO, China's not as bad as some when considering Air Pollution.

        --
        Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
        • (Score: 0) by Anonymous Coward on Friday January 26 2018, @07:43PM (1 child)

          by Anonymous Coward on Friday January 26 2018, @07:43PM (#628457)

          You are telling us that your issue with evolution is that you just can't imagine a rock lasting millions of years?

          • (Score: 2) by Freeman on Monday January 29 2018, @04:43PM

            by Freeman (732) on Monday January 29 2018, @04:43PM (#629866) Journal

            My issues with evolution are the conclusions that they jump to from what they say are an exact science. When the fact that they are giving such huge ranges of time implies that they have no idea what they are talking about. Yes, rock lasts a long time, but just looking at our own "recent history". We barely have bits of recognizable architecture, and Stone artifacts from recent history. Why would there be such a wealth of evidence of the Dinosaurs, if the dinosaurs lived Millions of years ago? Why wouldn't in that vast time period, something have happened to the evidence. Either through erosion, or earthquakes, or volcanoes, or any of the other supposed catastrophic things that may have happened in the mean time. Why are there fossils on the tops of Mountains that haven't been eroded over the vast time periods? Here's a thought, perhaps, the dinosaurs, and other things lived much, much closer in recent past. The reason why there's such a wealth of evidence of the Dinosaurs and fossils on the tops of the mountains and just lying on the surface of plains is that they lived not that long ago. The elements haven't had Millions of years to erode the evidence that they ever existed. "Q: In what state can you find a lot of dinosaur bones?
            A: Dinosaurs are found in 35 states and on every continent, wherever rocks from dinosaur time on ancient land are now on the surface. The best dinosaur-searching places are deserts and badlands out West. (Don Lessem)" https://www.scholastic.com/teachers/articles/teaching-content/locations-dinosaur-digs/ [scholastic.com]

            There's also the issue of Dinosaur Tracks. Why / How could have a track, survived for Millions of Years in a stream, or even just out on the surface? Shouldn't just air and sand, etc blowing over it have eroded it, or especially in the case of the Dinosaur Tracks in a stream with water eroding them. Erosion is a powerful force!

            "Q: Have you found any dinosaur bones in Austin, Texas? About how far did you dig to find the dinosaur bones?
            A: So far no one has found any dinosaurs here in Austin. But we have found some dinosaur tracks which are in the middle of one of the city's parks. They are from an ostrich-sized carnivorous dinosaur. Most of the rocks around here were deposited in the ocean, so we mostly find marine reptiles like mosasaurs and plesiosaurs inside the city. Strictly speaking, these are not dinosaurs but they are still very exciting to find. We found all of them by looking for bones lying on the surface of the ground. Only after we found some pieces did we know where to dig. The plesiosaur skeleton took about six weeks to dig up. The hole it came out of was not very deep but it took a long time because the rock it was in was very hard. (Tim Rowe)"

            --
            Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
        • (Score: 3, Informative) by bzipitidoo on Friday January 26 2018, @11:23PM (1 child)

          by bzipitidoo (4388) on Friday January 26 2018, @11:23PM (#628617) Journal

          Well, I'll give it a go.

          > evolution takes giant leaps of faith

          No. Science, including evolution, does not take anything whatsoever on faith. We do have to proceed with the proviso that what we observe is real. There may be an undetectable, deeper, possibly supernatural, reality underlying everything, but without any way to find out if there is and what its nature might be. Besides, no matter how deeply we probe, are able to probe, someone can always speculate that there's something deeper.

          Science and rationality have deservedly achieved a reputation as great tools for answering questions. Consequently, pseudo scientists are always trying to get an easy ride by asserting that some claim they're making is backed by science, when it isn't. Not always easy to spot them, but sadly, some religions are infested with them and those often are easy to spot.

          > stop trying to feed me the billions of years life creation story or the millions of years dinosaur theories.

          What's the basis for your contention that these time scales are too long to be credible? Entropy makes everything decay too fast for anything to occur over such large time scales? That's an assertion that can be tested, and the results are that matter does last an incredibly long time. Think of it from the viewpoint of inertia. Why shouldn't a rock or a fossilized bone, once it has settled into a local low energy state, remain unchanged, for billions or trillions of years, or even longer, absent some external agent to drive a change?

          > No, I don't think we're going to have that issue in the next 100 years. No, I don't think the polar ice caps are going to melt in that time, either.

          Frozen mammoths can't resist decay for 40,000 years, but ice caps can definitely resist melting for over 100 years of warmer weather?

          Anyway, many of the proposals are good ideas whether or not Global Warming is real and a problem. For instance, there's lots of room for improvement in traffic light timings. Red lights frequently delay travelers for nothing because they're too mindless to detect and respond to those cases when the direction with the green is empty of traffic. Making traffic lights smarter would save time and help with the Global Warming problem.

          • (Score: 2) by Freeman on Monday January 29 2018, @04:59PM

            by Freeman (732) on Monday January 29 2018, @04:59PM (#629871) Journal

            Evolution, isn't science. https://en.wikipedia.org/wiki/Scientific_method [wikipedia.org] The theory of evolution is just that.

            100 years is a much shorter time span than 40,000 years, so yeah, I stand by that. We can actually gather evidence for hundred year experiments and studies. Anything saying 40,000 years, is wild speculation.

            That being said, I do care about the planet and am hopeful that these "green energy" pushes will be more than political posturing. I hope they will make a difference in our pursuit of a cleaner environment.

            --
            Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(1)